Apparatus and method for multiplexing of integrated access and backhaul (iab) node in wireless communication system

ABSTRACT

The disclosure relates to a 5th Generation (5G) or 6th Generation (6G) communication system for supporting a higher data transmission rate. A method of operating an Integrated Access and Backhaul (IAB) donor node in a wireless communication system is provided. The method includes transmitting Frequency Division Multiplexing (FDM)-related information or Spatial Division Multiplexing (SDM)-related information to an IAB node, receiving necessary information from the IAB node, and transmitting or receiving backhaul data with respect to the IAB node by applying the FDM or the SMD, based on the FDM-related information or the SMD-related information.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. §119(a) of a Korean patent application number 10-2021-0060744, filed onMay 11, 2021, in the Korean Intellectual Property Office, and of aKorean patent application number 10-2021-0151461, filed on Nov. 5, 2021,in the Korean Intellectual Property Office, the disclosure of each ofwhich is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

The disclosure relates to a wireless communication system. Moreparticularly, the disclosure relates to a method and apparatus formultiplexing an Integrated Access and Backhaul (IAB) node.

2. Description of Related Art

5th Generation (5G) mobile communication technologies define broadfrequency bands such that high transmission rates and new services arepossible, and can be implemented not only in “Sub 6 Giga hertz (GHz)”bands such as 3.5 GHz, but also in “Above 6 GHz” bands referred to asmmWave including 28 GHz and 39 GHz. In addition, it has been consideredto implement 6^(th) Generation (6G) mobile communication technologies(referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3 THz bands) in order to accomplish transmission rates fiftytimes faster than 5G mobile communication technologies and ultra-lowlatencies one-tenth of 5G mobile communication technologies.

At the beginning of the development of 5G mobile communicationtechnologies, in order to support services and to satisfy performancerequirements in connection with enhanced Mobile BroadBand (eMBB), UltraReliable Low Latency Communications (URLLC), and massive Machine-TypeCommunications (mMTC), there has been ongoing standardization regardingbeamforming and massive Multiple-Input and Multiple-Output (MIMO) formitigating radio-wave path loss and increasing radio-wave transmissiondistances in mmWave, supporting numerologies (for example, operatingmultiple subcarrier spacings) for efficiently utilizing mmWave resourcesand dynamic operation of slot formats, initial access technologies forsupporting multi-beam transmission and broadbands, definition andoperation of BandWidth Part (BWP), new channel coding methods such as aLow Density Parity Check (LDPC) code for large amount of datatransmission and a polar code for highly reliable transmission ofcontrol information, L2 pre-processing, and network slicing forproviding a dedicated network specialized to a specific service.

Currently, there are ongoing discussions regarding improvement andperformance enhancement of initial 5G mobile communication technologiesin view of services to be supported by 5G mobile communicationtechnologies, and there has been physical layer standardizationregarding technologies such as Vehicle-to-everything (V2X) for aidingdriving determination by autonomous vehicles based on informationregarding positions and states of vehicles transmitted by the vehiclesand for enhancing user convenience, New Radio Unlicensed (NR-U) aimed atsystem operations conforming to various regulation-related requirementsin unlicensed bands, NR User Equipment (UE) Power Saving,Non-Terrestrial Network (NTN) which is UE-satellite direct communicationfor providing coverage in an area in which communication withterrestrial networks is unavailable, and positioning.

Moreover, there has been ongoing standardization in air interfacearchitecture/protocol regarding technologies such as Industrial Internetof Things (IIoT) for supporting new services through interworking andconvergence with other industries, Integrated Access and Backhaul (IAB)for providing a node for network service area expansion by supporting awireless backhaul link and an access link in an integrated manner,mobility enhancement including conditional handover and Dual ActiveProtocol Stack (DAPS) handover, and two-step random access forsimplifying random access procedures (2-step random-access channel(RACH) for NR). There also has been ongoing standardization in systemarchitecture/service regarding a 5G baseline architecture (for example,service based architecture or service based interface) for combiningNetwork Functions Virtualization (NFV) and Software-Defined Networking(SDN) technologies, and Mobile Edge Computing (MEC) for receivingservices based on UE positions.

As 5G mobile communication systems are commercialized, connected devicesthat have been exponentially increasing will be connected tocommunication networks, and it is accordingly expected that enhancedfunctions and performances of 5G mobile communication systems andintegrated operations of connected devices will be necessary. To thisend, new research is scheduled in connection with eXtended Reality (XR)for efficiently supporting Augmented Reality (AR), Virtual Reality (VR),Mixed Reality (MR) and the like, 5G performance improvement andcomplexity reduction by utilizing Artificial Intelligence (AI) andMachine Learning (ML), AI service support, metaverse service support,and drone communication.

Furthermore, such development of 5G mobile communication systems willserve as a basis for developing not only new waveforms for providingcoverage in terahertz bands of 6G mobile communication technologies,multi-antenna transmission technologies such as Full Dimensional MIMO(FD-MIMO), array antennas and large-scale antennas, metamaterial-basedlenses and antennas for improving coverage of terahertz band signals,high-dimensional space multiplexing technology using Orbital AngularMomentum (OAM), and Reconfigurable Intelligent Surface (RIS), but alsofull-duplex technology for increasing frequency efficiency of 6G mobilecommunication technologies and improving system networks, AI-basedcommunication technology for implementing system optimization byutilizing satellites and AI from the design stage and internalizingend-to-end AI support functions, and next-generation distributedcomputing technology for implementing services at levels of complexityexceeding the limit of UE operation capability by utilizingultra-high-performance communication and computing resources.

Meanwhile, the Internet has evolved from a human-based connectionnetwork, in which humans create and consume information, to the Internetof Things (IoT), in which distributed elements, such as objects,exchange information with each other to process the information. AnInternet of Everything (IoE) technique is emerging, in which a techniquerelated to the IoT is combined with, for example, a technique forprocessing big data through connection with a cloud server or the like.In order to implement the IoT, various technological components arerequired, such as a sensing technique, wired/wireless communication andnetwork infrastructures, a service interface technique, a securitytechnique, or the like. Therefore, in recent years, a techniqueincluding a sensor network for connecting objects, Machine to Machine(M2M) communication, Machine Type Communication (MTC), or the like havebeen studied. In the IoT environment, intelligent Internet Technology(IT) services may be provided to collect and analyze data obtained fromconnected objects to create new value in human life. As existingInformation Technology (IT) techniques and various industries convergeand combine with each other, the IoT may be applied to various fields,such as smart homes, smart buildings, smart cities, smart cars orconnected cars, smart grids, health care, smart home appliances,high-quality medical services, etc.

Accordingly, various attempts are being made to apply 5G communicationsystems to the IoT network. For example, techniques related to sensornetworks, M2M communication, MTC, etc., are being implemented by using a5G communication technique including beam-forming, Multiple-Input andMultiple-Output (MIMO), array antennas, etc. The application ofcloud-Radio Access Network (RAN) as a big data processing techniquedescribed above may be an example of convergence of the 5G communicationtechnique and the IoT technique.

Various studies have recently been conducted to utilize an IABtechnique, which requires improvement of a dual connectivity of an IABnode.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the disclosure is to providea method and apparatus for multiplexing a resource of a Distributed Unit(DU) and Mobile Termination (MT) of an Integrated Access and Backhaul(IAB) node in a wireless communication system.

Another aspect of the disclosure is to provide a DU resource type forsupporting Frequency Division Multiplexing (FDM) of an IAB node, and anoperation of the IAB node.

Another aspect of the disclosure is to provide a DU resource type forsupporting Spatial Division Multiplexing (SDM) of an IAB node, and anoperation of the IAB node.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, a method of operating anIntegrated Access and Backhaul (IAB) donor node in a wirelesscommunication system is provided. The method includes transmittingFrequency Division Multiplexing (FDM)-related information or SpatialDivision Multiplexing (SDM)-related information to an IAB node,receiving necessary information from the IAB node, and transmitting orreceiving backhaul data with respect to the IAB node by applying the FDMor the SMD, based on the FDM-related information or the SMD-relatedinformation.

In accordance with another aspect of the disclosure, a method ofoperating an IAB node in a wireless communication system is provided.The method includes receiving FDM-related information or SDM-relatedinformation from an IAB donor node, transmitting necessary informationto the IAB donor node, and transmitting or receiving backhaul data withrespect to the IAB donor node by applying the FDM or the SMD, based onthe FDM-related information or the SMD-related information.

An apparatus and method according to embodiments of the disclosureprovide an apparatus and method for reducing transmission/receptioninterference between a Distributed Unit (DU) and Mobile Termination (MT)of an Integrated Access and Backhaul (IAB) node, when a resource of theDU and MT of the IAB node is multiplexed using Frequency DivisionMultiplexing (FDM).

An apparatus and method according to embodiments of the disclosureprovide an apparatus and method for transmitting/receiving data, when aresource of a DU and MT of an IAB node is multiplexed using SpatialDivision Multiplexing (SDM).

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates an example of a wireless communication system inwhich an Integrated Access and Backhaul (IAB) node operates according toan embodiment of the disclosure;

FIGS. 2A and 2B schematically illustrate examples in which resources aremultiplexed between an access link and a backhaul link in an IAB nodeaccording to various embodiments of the disclosure;

FIGS. 3A and 3B illustrate examples in which resources are multiplexedin a time domain between an access link and a backhaul link in an IABnode according to various embodiments of the disclosure;

FIGS. 4A and 4B illustrate examples in which resources are multiplexedin frequency and spatial domains between an access link and a backhaullink in an IAB node according to various embodiments of the disclosure;

FIG. 5 schematically illustrates a structure of an IAB node according toan embodiment of the disclosure;

FIG. 6 is a drawing for explaining a communication method forsimultaneously performing transmission/reception between a MobileTermination (MT) and Distributed Unit (DU) in an IAB node in a wirelesscommunication system according to an embodiment of the disclosure;

FIG. 7 is a drawing for explaining a DU resource type for supportingFrequency Division Multiplexing (FDM) of an IAB node and an operation ofan IAB node in a wireless communication system according to anembodiment of the disclosure;

FIG. 8 illustrates a DU resource type for supporting Spatial DivisionMultiplexing (SDM) of an IAB node and an operation of the IAB node in awireless communication system according to an embodiment of thedisclosure;

FIG. 9A illustrates an operation of a base station/parent IAB node in awireless communication system according to an embodiment of thedisclosure;

FIG. 9B illustrates an operation of an IAB node which is a child IABnode in a wireless communication system according to an embodiment ofthe disclosure;

FIG. 10 illustrates a structure of a terminal according to an embodimentof the disclosure;

FIG. 11 illustrates a structure of a base station (a donor base station)according to an embodiment of the disclosure; and

FIG. 12 illustrates a structure of an IAB node according to anembodiment of the disclosure.

The same reference numerals are used to represent the same elementsthroughout the drawings.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thedisclosure. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

Terms used and words in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of thedisclosure is provided for illustration purpose only and not for thepurpose of limiting the disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

All terms (including technical and scientific terms) used herein havethe same meaning as commonly understood by those ordinarily skilled inthe art disclosed in the disclosure. It will be further understood thatterms, such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art, and will not be interpreted in anidealized or overly formal sense unless expressly so defined herein.Optionally, the terms defined in the disclosure should not beinterpreted to exclude the embodiments of the disclosure.

A hardware-based approach is described for example in the variousembodiments of the disclosure described hereinafter. However, since thevarious embodiments of the disclosure include a technique in whichhardware and software are both used, a software-based approach is notexcluded in the embodiments of the disclosure.

Although terms related to signals and messages used in the followingdescription (e.g., Radio Resource Control (RRC) signaling, messages,signals, Non-Access Stratum (NAS) messages, NAS signaling) are describedbased on terms defined in current 3rd Generation Partnership Project(3GPP) Long Term Evolution (LTE) or New Radio (NR) standards, otherterms having equivalent technical meanings may also be used. Inaddition, terms (e.g., a base station, a terminal, a communication node,a radio node, a radio unit, a network node, a Master Node (MN), aSecondary Node (SN), a Transmission/Reception Point (TRP), a DigitalUnit (DU), a Radio Unit (RU), a Radio Access Network (RAN) node, an eNB,a gNB, an Access and Mobility Management Function (AMF), a Central Unit(CU), or the like) referring to network entities used in the followingdescription are disclosed to describe embodiments. Therefore, thedisclosure is not limited to the terms described below, and other termshaving equivalent technical meanings may also be used.

In addition, the disclosure describes various embodiments by using termsused in some communication standards (e.g., LTE and NR defined in 3GPP).A 3GPP mobile communication system described herein may include both 4thgeneration (4G) (hereinafter, LTE) and 5G (hereinafter, NR). However,embodiments of the disclosure may be easily modified and applied also toother communication systems in addition to the 3GPP mobile communicationsystem.

In addition, although an expression ‘greater than’ or ‘less than’ isused in the disclosure to determine whether a specific condition issatisfied or fulfilled, this does not exclude an expression of ‘greaterthan or equal to’ or ‘less than or equal to’. A condition described as“greater than or equal to” may be replaced with “greater than”. Acondition described as “less than or equal to” may be replaced with“less than”. A condition described as “greater than or equal to and lessthan” may be replaced with “greater than and less than or equal to”.

Embodiments of the disclosure will be described herein below withreference to the accompanying drawings. In this case, it should be notedthat like reference numerals denote like constitutional elements in theaccompanying drawings. In the following description, well-knownfunctions or constructions are not described in detail since they wouldobscure the disclosure in unnecessary detail.

In describing the embodiments, descriptions which are well known in thetechnical field to which the disclosure belongs and are not relateddirectly to the disclosure will be omitted. This is to convey thedisclosure more clearly by omitting unnecessary description.

For the same reason, some components may be exaggerated, omitted, orschematically illustrated in the accompanying drawings. Also, a size ofeach component does not completely reflect an actual size. In thedrawings, like reference numerals denote like or correspondingcomponents.

Advantages and features of the disclosure and methods of accomplishingthe same may be understood more clearly by reference to the followingdetailed description of the embodiments and the accompanying drawings.However, the disclosure is not limited to embodiments disclosed below,and may be implemented in various forms. Rather, the embodiments areprovided to complete the disclosure and to fully convey the concept ofthe disclosure to one of those ordinarily skilled in the art, and thedisclosure will only be defined by the scope of claims. Throughout thespecification, like reference numerals denote like components.

In this case, it will be understood that blocks of processing flowdiagrams and combinations of the flow diagrams may be performed bycomputer program instructions. Since these computer program instructionsmay be loaded into a processor of a general purpose computer, a specialpurpose computer, or another programmable data processing apparatus, theinstructions, which are performed by a processor of a computer oranother programmable data processing apparatus, create a means forperforming functions described in the block(s) of the flow diagram. Thecomputer program instructions may be stored in a computer-usable orcomputer-readable memory capable of directing a computer or anotherprogrammable data processing apparatus to implement a function in aparticular manner, and thus the instructions stored in thecomputer-usable or computer-readable memory may also be capable ofproducing manufacturing items containing an instruction means forperforming the functions described in the block(s) of the flow diagram.The computer program instructions may also be loaded into a computer oranother programmable data processing apparatus, and thus, instructionsfor operating the computer or another programmable data processingapparatus by generating a computer-executed process when a series ofoperations are performed in the computer or another programmable dataprocessing apparatus may provide operations for performing the functionsdescribed in the block(s) of the flow diagram.

In addition, each block may represent part of a module, segment, or codewhich includes one or more executable instructions for executingspecified logical function(s). It should also be noted that in somealternative implementations, functions mentioned in blocks may occur notin an orderly manner. For example, two blocks illustrated successivelymay actually be executed substantially concurrently, or the blocks maysometimes be performed in a reverse order according to correspondingfunctions.

The term ‘unit’ used herein means a software or hardware component, suchas a Field Programmable Gate Array (FPGA) or Application SpecificIntegrated Circuit (ASIC), which performs certain tasks. However, the‘unit’ is not limited to the software or hardware component. The ‘unit’may be configured to reside on an addressable storage medium andconfigured to execute on one or more processors. Thus, for example, the‘unit’ may include components, such as software components,object-oriented software components, class components, and taskcomponents, processes, functions, attributes, procedures, subroutines,segments of program code, drivers, firmware, microcode, circuitry, data,databases, data structures, tables, arrays, and variables. Thefunctionality provided in the components and ‘units’ may be combinedinto fewer components or further separated into additional componentsand units. In addition thereto, the components and units may beimplemented to reproduce one or more Central Processing Units (CPUs)included in a device or a security multimedia card.

A wireless communication system is developed to a broadband wirelesscommunication system which provides a high-speed and high-quality packetdata service beyond the early voice-oriented services as in acommunication standard, for example, High Speed Packet Access (HSPA),Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access(E-UTRA), or LTE-advanced (LTE-A) of 3GPP, High Rate Packet Data (HRPD)or Ultra Mobile Broadband (UMB) of 3GPP2, and 802.16e or the like ofIEEE.

As a representative example of the broadband wireless communicationsystem, the LTE system has adopted an Orthogonal Frequency DivisionMultiplexing (OFDM) scheme in a DownLink (DL) and has adopted a SingleCarrier Frequency Division Multiple Access (SC-FDMA) scheme in an UpLink(UL). The UL refers to a radio link through which a terminal (a UserEquipment (UE) or a Mobile Station (MS)) transmits data or a controlsignal to a Base Station (BS) (e.g., eNodeB), and the DL refers to aradio link through which the BS transmits data or a control signal tothe terminal. In such a multiple access scheme, data or controlinformation of each user is classified by generally assigning andoperating the data or control information such that time-frequencyresources for transmitting data or control information for each user donot overlap each other, that is, such that orthogonality is established.

As a future communication system after LTE system, a 5G (or NR)communication system has to be able to freely reflect variousrequirements of a user and a service provider, and thus, servicessatisfying various requirements at the same time need to be supported.The services considered for the 5G communication system include enhancedMobile BroadBand (eMBB), massive Machine Type Communication (mMTC),Ultra Reliability Low Latency Communication (URLLC), etc.

The eMBB aims to provide a higher data rate than a data rate supportedby the existing LTE, LTE-A, or LTE-Pro. For example, in the 5Gcommunication system, the eMBB shall be able to provide a peak data rateof 20 Gbps in the DL and a peak data rate of 10 Gbps in the UL from theviewpoint of one BS. In addition, the 5G communication system shallprovide an increased user-perceived data rate simultaneously withproviding the peak data rate. In order to satisfy such requirements,improvement of various transmitting/receiving techniques including afurther improved Multiple-Input and Multiple-Output (MIMO) transmissiontechnique is required. In addition, signals are transmitted using atransmission bandwidth of up to 20 MHz in a 2 GHz band used in thecurrent LTE, but the 5G communication system uses a bandwidth wider than20 MHz in a frequency band of 3 to 6 GHz or more than 6 GHz, therebysatisfying a data rate required in the 5G communication system.

At the same time, mMTC is being considered to support applicationservices such as Internet of Things (IoT) in the 5G communicationsystem. The mMTC is required for an access support of a large-scaleterminal in a cell, coverage enhancement of a terminal, improved batterytime, and cost reduction of the terminal in order to efficiently providethe IoT. The IoT needs to be able to support a large number of terminals(e.g., 1,000,000 terminals/km2) in a cell because it is attached tovarious sensors and various devices to provide communication functions.In addition, the terminals supporting the mMTC are more likely to bepositioned in shaded areas not covered by a cell, such as an undergroundof a building due to nature of services, and thus, the terminal requiresa wider coverage than other services provided by the 5G communicationsystem. The terminals which support the mMTC shall be configured asinexpensive terminals and require very long battery lifetime, such as 10to 15 years, because it is difficult to frequently replace batteries ofthe terminals.

Lastly, the URLLC is a cellular-based wireless communication system usedfor a specific purpose (mission-critical). For example, a service usedin remote control for a robot or machinery, industrial automation,unmanned aerial vehicle, remote health care, or emergency alert may beconsidered. Accordingly, communication provided by the URLLC shallprovide very low latency and very high reliability. For example, aservice supporting the URLLC shall satisfy air interface latency smallerthan 0.5 milliseconds and at the same time, has a packet error rate of10⁻⁵ or less. Accordingly, for the service supporting the URLLC, the 5Gsystem is required to provide a Transmit Time Interval (TTI) shorterthan those for other services while securing reliable communicationlinks by allocating a broad resource in a frequency band.

The three services, that is, eMBB, URLLC, and mMTC, of 5G may betransmitted by being multiplexed in one system. In this case, theservices may use different transmission/reception methods andtransmission/reception parameters in order to meet differentrequirements thereof.

In the following description, terms for identifying an access node,terms referring to network entities, a term referring to message, termsreferring to interfaces between network entities, terms referring to avariety of identification information, or the like are exemplified forconvenience of explanation. Therefore, the disclosure is not limited tothe terms described below, and other terms having equivalent technicalmeanings may also be used.

Hereinafter, for convenience of explanation, terms and names defined inLTE and NR standards, which are the latest standard defined in the 3GPPorganization among communication standards currently existing atpresent, are used in the disclosure. However, the disclosure is notlimited to the terms and names, and is also equally applied to a systemconforming to other standards. In particular, the disclosure may beapplied to 3GPP NR (5G communication standard).

With an increase in a frequency band (e.g., at least 6 GHz band, inparticular, mmWave band), a 5G system may have limited coverage due topropagation path attenuation, when a base station transmits/receivesdata with respect to a terminal. A plurality of relays (or relay nodes)may be deployed densely between propagation paths of the base stationand the terminal to solve the problem caused by the coverage limitation.Accordingly, however, an optical cable to be installed for a backhaulconnection between one relay to another relay results in a serious costproblem. Therefore, instead of installing the optical cable between therelays, a radio frequency resource of a wideband available in mmWave maybe used to transmit/receive backhaul data between the relays, therebysolving the cost problem occurring when the optical cable is installedand allowing the mmWave band to be used more efficiently.

As described, a technique for transmitting/receiving backhaul data froma base station and transmitting/receiving the data via at least onerelay node so that access data is finally transmitted/received to aterminal is called Integrated Access and Backhaul (IAB). In this case, arelay node which transmits/receives data from the base station by usinga radio backhaul is called an IAB node. In this case, the base station(or also referred to as a gNB, an IAB donor, etc.) is constructed of aCentral Unit (CU) and a Distributed Unit (DU), and the IAB node isconstructed of a DU and a Mobile Termination (MT). The CU is responsiblefor the DU of all IAB nodes coupled to the base station through amulti-hop.

The IAB node may use different frequency bands or the same frequencyband when backhaul data is received from the base station and accessdata is transmitted to the terminal and when access data is receivedfrom the terminal and backhaul data is transmitted to the base station.When the same frequency is used in access data reception and backhauldata transmission or in access data transmission and backhaul datareception, the IAB node has half-duplex constraints at a moment.Accordingly, as a method of reducing a transmission/reception delaycaused by the half-duplex constraints of the IAB mode, when the IAB nodetransmits a signal, multiplexing (e.g., FDM and/or SMD) may be performedon backhaul data (e.g., when assuming a situation where a parent IABnode, an IAB node operating as a relay node, and a child node arecoupled through a radio backhaul link, uplink data from the MT of theIAB node to the DU of the parent IAB node and downlink data from the DUof the IAB node to the MT of the child IAB node) and access data to theterminal (downlink data from the IAB node to the terminal). TS 38.300section 4.7 Integrated Access and Backhaul of the 3GPP standard may beused by reference for a relationship between the parent node and childnode for the IAB node.

In addition, when the IAB node receives a signal, multiplexing (FDMand/or SDM) may also be performed on backhaul data (downlink data fromthe DU of the parent IAB node to the MT of the IAB node and uplink datafrom the MT of the child IAB node to the DU of the IAB node) and accessdata from the terminal (uplink data from the terminal to the IAB node).

In this case, when the multiplexing scheme (FDM and/or SDM) issupported, it may be necessary to standardize a DU resource type of theIAB node for cooperation between the IAB node and the parent IAB nodeand an operation of the DU and MT of the IAB node in each DU resourcetype. Hereinafter, embodiments of the disclosure provide a method ofconfiguring the DU resource type of the IAB node and an operation of theIAB node based thereon when the multiplexing scheme (FDM and/or SDM) issupported.

FIG. 1 illustrates an example of a wireless communication system inwhich an IAB node operates according to an embodiment of the disclosure.

Referring to FIG. 1, a gNB 101 is a typical base station (e.g., an eNBor a gNB), and may be called a gNB, an eNB, a donor base station, or adonor IAB in the disclosure. The IAB donor may imply an entity whichserves the IAB node so that an IAB node described below is coupled to acore network (e.g., an Evolved Packet Core (EPC) or a 5G Core (5GC)).The IAB donor, as a base station, is a network infrastructure whichprovides radio access to a terminal. The base station has coveragedefined as a specific geographic area, based on a distance capable oftransmitting/receiving a signal. Hereinafter, the term ‘coverage’ may beused to refer to a service coverage area in a base station. The basestation may cover one cell, or may cover a plurality of cells. Herein,the plurality of cells may be identified by a frequency to be supportedand an area of a covered sector.

The base station which is responsible for the IAB donor may be referredto as not only the gNB but also an ‘Access Point (AP)’, an ‘eNodeB(eNB)’, a ‘5th Generation (5G) node’, a ‘5G NodeB (NB)’, a ‘nextgeneration NodeB (gNB)’, a ‘wireless point’, a ‘Transmission/ReceptionPoint (TRP)’, or other terms having equivalent technical meanings. Inaddition, in case of distributed deployment, the base station may bereferred to as a Centralized Unit (CU), a Distributed Unit (DU), aDigital Unit (DU), a Radio Unit (RU), a Remote Radio Head (RRH), orother terms having equivalent technical meanings. Although the IABdonor, i.e., the gNB 101, is described in FIG. 1 as one entity, it mayalso be implemented as distributed entities according to an embodiment.For example, the IAB donor may function by being divided into a CU and aDU.

An IAB node #1 111 and an IAB node #2 121 are IAB nodes whichtransmit/receive a signal through a backhaul link. As a network entityfor radio access and backhaul connectivity, the IAB nodes 111 and 112may be deployed to increase coverage. Since the backhaul connectivity isconfigured in a wireless manner, coverage of the gNB 101 which is an IABdonor may be increased without having to install a wired network. Forexample, the IAB node #1 111 may be deployed around the gNB 101 which isthe IAB donor (e.g., within a radio communication radius). The IAB node#1 111 may perform communication by being coupled to the gNB 101 whichis the IAB donor through a backhaul link, and may perform communicationwith a UE #2 112 through a radio link. In addition, the IAB node #2 121may be deployed around the IAB node #1 111 which is another node (e.g.,within a radio communication radius). Coverage may be increased in ahigh frequency band (e.g., a mmWave band) by deploying each IAB node.Each IAB node may perform not only multi-hop but also relay techniquesor a repeater function.

The IAB node may be coupled to a parent node and a child node. Forexample, from the viewpoint of the IAB node #1 111, the gNB 101 may bereferred to as a parent node, and the IAB node #2 121 or the UE #2 112may be referred to as a child node. In addition, from the viewpoint ofthe IAB node #2 121, the IAB node #1 111 may be referred to as a childnode. A link between the IAB node and the parent node is referred to asa parent link, and a link between the IAB node and the child node isreferred to as a child link.

The terminal (e.g., a UE #1 102, the UE #2 112, and a UE #3 122) is adevice used by a user, and communicates with the base station or the IABnode through a wireless channel. Hereinafter, the wireless channelbetween the terminal and the base station or between the terminal andthe IAB node is referred to as an access link. In the disclosure, theterminal may include not only an electronic device used by a generaluser but also, optionally, a device which performs Machine TypeCommunication (MTC) operable without a user's intervention. The terminalmay be referred to as a ‘User Equipment (UE)’, a ‘mobile station’, a‘subscriber station’, a ‘Customer Premises Equipment (CPE)’, a ‘remoteterminal’, a ‘wireless terminal’, an ‘electronic device’, a ‘vehicleterminal’, a ‘user device’, or other terms having equivalent technicalmeanings.

The UE #1 102 may transmit/receive access data with respect to the gNB101 through an access link 103. The IAB node #1 111 may transmit/receivebackhaul data with respect to the gNB 101 through a backhaul link 104.The UE #2 112 may transmit/receive access data with respect to the IABnode #1 111 through an access link 113. The IAB node #2 121 maytransmit/receive backhaul data with respect to the IAB node #1 111through a backhaul link 114. Accordingly, the IAB node #1 111 is ahigher IAB node of the IAB node #2 121, and is called a parent IAB node,and the IAB node #2 121 is a lower IAB node of the IAB node #1 111, andis called a child IAB node. The UE #3 122 transmits/receives accessdata. With respect to the IAB node #2 121 through an access link 123. InFIG. 1, the backhaul links 104 and 114 may use a radio backhaul link.

Hereinafter, the disclosure describes measurement on an IAB node of aterminal or a donor gNB.

In order for the UE #2 112 or the UE #3 122 to perform measurement on anIAB node or a neighboring donor gNB other than a serving IAB node,coordination may be required between the donor gNB and the IAB nodes.That is, the donor gNB may match a measurement resource of an IAB nodehaving an even-numbered hop order or match a measurement resource of anIAB node having an odd-numbered hop order, so that the terminalminimizes waste of resources for performing measurement of a neighboringIAB node or an IAB base station. For measurement of the neighboring IABnode, the terminal may receive configuration information indicatingmeasurement of Synchronization Signal Block (SSB)/Physical BroadcastChannel (PBCH) or Channel State Information Reference Signal (CSI-RS)from the serving IAB node or base station through higher-layer signaling(a higher-layer signal, e.g., Radio Resource Control (RRC) signaling).If the terminal is configured to measure a neighboring base stationthrough the SSB/PBCH, at least two SSB/PBCH Measurement TimingConfigurations (SMTCs) may be configured for each frequency in theterminal for measurement resources of the IAB node having theeven-numbered hop order or measurement resources of the IAB node havingthe odd-numbered hop order. The terminal which has received theconfiguration information may perform measurement of the IAB node havingthe even-numbered hop order in one SMTC, and may perform measurement ofthe IAB node having the odd-numbered hop order in another SMTC.

Hereinafter, the disclosure describes measurement on an IAB node oranother IAB node of donor gNBs.

In order for one IAB node to perform measurement on another neighboringdonor gNB or IAB node, coordination may be required between the donorgNB and IAB nodes. That is, the donor gNB may match a measurementresource of an IAB node having an even-numbered hop order or match ameasurement resource of an IAB node having an odd-numbered hop order, sothat one IAB node minimizes waste of resources for performingmeasurement of a neighboring IAB node or an IAB base station. Formeasurement of the neighboring IAB node, one IAB node may receiveconfiguration information indicating measurement of SSB/PBCH or CSI-RSfrom a serving IAB node or base station through higher-layer signaling(a higher-layer signal, e.g., RRC signaling). If the IAB node isconfigured to measure a neighboring base station through the SSB/PBCH,at least two SSB/PBCH Measurement Timing Configurations (SMTCs) may beconfigured for each frequency in the IAB node for measurement resourcesof the IAB node having the even-numbered hop order or measurementresources of the IAB node having the odd-numbered hop order. The IABnode which has received the configuration information may performmeasurement of the IAB node having the even-numbered hop order in oneSMTC, and may perform measurement of the IAB node having theodd-numbered hop order in another SMTC.

Hereinafter, in an IAB technique proposed in the disclosure, it isdescribed in greater detail with reference to FIGS. 2A, 2B, 3A, 3B, 4A,and 4B that a backhaul link between a base station and an IAB node orbetween one IAB node and another IAB node and an access link between abase station and a terminal or between an IAB node and a terminal aremultiplexed in a radio resource.

FIGS. 2A and 2B schematically illustrate examples in which resources aremultiplexed between an access link and a backhaul link in an IAB nodeaccording to various embodiments of the disclosure.

Referring to FIG. 2A, it illustrates an example in which resources aremultiplexed in a time domain between an access link and a backhaul linkin an IAB node. FIG. 2B illustrates an example in which resources aremultiplexed in a frequency domain between an access link and a backhaullink in an IAB node.

FIG. 2A illustrates an example in which a backhaul link 203 between abase station and an IAB node or between an IAB node and another IAB nodeand an access link 202 between a base station and a terminal or betweenan IAB node and a terminal are subjected to Time Domain Multiplexing(TDM) in a radio resource 201.

When resources are multiplexed in the time domain between the accesslink and the backhaul link in the IAB node as shown in FIG. 2A, data isnot transmitted/received between the base station and the IAB node inthe time domain in which the base station or the IAB nodetransmits/receive data with respect to the terminal. In addition, whenresources are multiplexed in the time domain between the access link andthe backhaul link in the IAB node, the base station or the IAB node doesnot transmit/receive data with respect to the terminal in the timedomain in which data is transmitted/received between the base stationand the IAB nodes.

FIG. 2B illustrates an example in which a backhaul link 213 between abase station and an IAB node or between an IAB node and another IAB nodeand an access link 212 between a base station and a terminal or betweenan IAB node and a terminal are subjected to Frequency DomainMultiplexing (FDM) in a radio resource 211. Therefore, it is possible totransmit/receive data between the base station and the IAB node in atime domain in which the base station or the IAB node transmits/receivesdata with respect to the terminal. However, only data transmission inthe same direction is possible due to half-duplex constraints of IABnodes. For example, in the time domain in which a first IAB nodereceives data from the terminal, the first IAB node is able to receiveonly backhaul data from another IAB node or the base station. Inaddition, in the time domain in which the first IAB node transmits datato the terminal, the first IAB node is able to transmit only backhauldata to another IAB node or the base station.

Although only TDM and FDM are described in FIGS. 2A and 2B amongmultiplexing schemes, Spatial Domain Multiplexing (SDM) is possiblebetween an access link and a backhaul link. Therefore, althoughtransmission/reception between the access link and the backhaul link arepossible at the same time through the SDM, only data transmission in thesame direction is possible in the SDM due to half-duplex constraints ofthe IAB nodes as in the FDM of FIG. 2B above. For example, in the timedomain in which the first IAB node receives data from the terminal, thefirst IAB node is able to only receive backhaul data from another IABnode or the base station. In addition, in the time domain in which thefirst IAB node transmits data to the terminal, the first IAB node isable to only transmit backhaul data to another IAB node or the basestation.

Information regarding which multiplexing scheme will be used among theTDM, the FDM, and the SDM may be transferred between the ‘IAB node’ andthe ‘base station or higher IAB node’ in various manners. According toembodiments, when the IAB node initially accesses to the base station orthe higher IAB node, the IAB node may transmit capability informationfor the multiplexing scheme to the base station or the higher IAB node(e.g., the parent IAB node). Alternatively, according to embodiments,the IAB node may receive information regarding which multiplexing schemewill be used from a corresponding base station or higher IAB nodesthrough system information or higher layer signaling information (ahigher layer signal) such as Radio Resource Control (RRC) information orMedium Access Control (MAC) Control Element (CE).

Alternatively, according to embodiments, after initial access,information regarding which multiplexing schemes will be used may bereceived from the base station or the higher IAB nodes through abackhaul link. Alternatively, according to embodiments, after the IABnode transmits the capability information to the base station or thehigher IAB node, which multiplexing scheme will be used may beimplemented by the IAB node, and which multiplexing scheme will be usedduring a specific slot or radio frame or a specific duration orcontinuously thereafter may be reported to the base station or thehigher IAB nodes through backhaul or higher layer signaling information.

Although the multiplexing scheme between the access link and thebackhaul link has been mainly described in FIGS. 2A and 2B, multiplexingused between one backhaul link and another backhaul link may be the sameas the multiplexing used between the access link and the backhaul link.For example, multiplexing of (a backhaul link of) a Mobile Termination(MT) and (a backhaul link or an access link of) a DU in an IAB node tobe described below may be described according to the method described inthe example of FIGS. 2A and 2B.

FIGS. 3A and 3B illustrate examples in which resources are multiplexedin a time domain between an access link and a backhaul link in an IABnode according to various embodiments of the disclosure.

Referring to FIGS. 3A and 3B, a process in which an IAB node 302communicates with a parent node 301, a child IAB node (a child node)303, and a UE 304 is exemplified in FIG. 3A. A link between respectivenodes will be described in greater detail. The parent node 301 maytransmit a backhaul downlink signal to the IAB node 302 through abackhaul downlink L_(P,DL) 311. The IAB node 302 may transmit a backhauluplink signal to the parent node 301 through a backhaul uplink L_(P,UL)312. The IAB node 302 may transmit an access downlink signal to the UE304 through an access downlink L_(A,DL) 316. The UE 304 may transmit anaccess uplink signal to the IAB node 302 through an access uplinkL_(A,UL) 315. The IAB node 302 may transmit a backhaul downlink signalto the child IAB node 303 through a backhaul downlink L_(C,DL) 313. Thechild IAB node 303 may transmit a backhaul uplink signal to the IAB node302 through a backhaul uplink L_(C,UL) 314. In the aforementionedexample of FIGS. 3A and 3B, a subscript P means a backhaul link with theparent, a subscript A means an access link with the UE, and a subscriptC means a backhaul link with the child.

A link relationship of FIGS. 3A and 3B is described based on the IABnode 302. From the viewpoint of the child IAB node 303, the parent nodeis the IAB node 302, and the child IAB node 303 may have another IABchild node at a lower level. In addition, from the viewpoint of theparent node 301, the child node is the IAB node 302, and the parent node301 may have another IAB parent node at a higher level.

In the description above, a backhaul uplink/downlink signal and anaccess uplink/downlink signal may include data and control information,or a channel for transmitting the data and control information, or areference signal required to decode the data and control information, orat least one of reference signals for reporting channel information.

FIG. 3B illustrates an example in which all of the aforementioned linksare multiplexed in a time domain. In the example of FIGS. 3A and 3B, thebackhaul downlink L_(C,DL) 313, the access downlink L_(A,DL) 316, theaccess uplink L_(A,UL) 315, the backhaul uplink L_(C,UL) 314, and thebackhaul uplink L_(P,UL) 312 are multiplexed in time order. The order oflinks proposed in the example of FIGS. 3A and 3B is for exemplarypurposes only, and any order may be applied without conditions.

Since the links are multiplexed in the time domain in time order, when asignal is transmitted from the parent node 301 to the child IAB node 303via the IAB node 302 and the signal is transmitted to the terminal inthis time-division manner, it can be seen that this is a multiplexingscheme which takes a lot of time. Accordingly, a method in whichtransmission is performed at the same time by multiplexing a backhaullink and another backhaul link or a backhaul link and an access link ina frequency domain or a spatial domain may be considered as a method forreducing a latency when the signal is finally transmitted from theparent node 301 to the terminal.

FIGS. 4A and 4B illustrate examples in which resources are multiplexedin frequency and spatial domains between an access link and a backhaullink in an IAB node according to various embodiments of the disclosure.

In FIGS. 4A and 4B, a method for reducing a latency by multiplexing abackhaul link and another backhaul link or a backhaul link and an accesslink in a frequency domain or in a spatial domain is described.

Referring to FIGS. 4A and 4B, similarly to FIGS. 3A and 3B, a process inwhich an IAB node 402 communicates with a parent node 401, a child IABnode 403, and a UE 404 is exemplified in FIG. 4A. A link betweenrespective nodes will be described in greater detail. The parent node401 may transmit a backhaul downlink signal to the IAB node 402 througha backhaul downlink L_(P,DL) 411. The IAB node 402 may transmit abackhaul uplink signal to the parent node 401 through a backhaul uplinkL_(P,UL) 412. The IAB node 402 may transmit an access downlink signal tothe UE 404 through an access downlink L_(A,DL) 416. The UE 404 maytransmit an access uplink signal to the IAB node 402 through an accessuplink L_(A,UL) 415. The IAB node 402 may transmit a backhaul downlinksignal to the child IAB node 403 through a backhaul downlink L_(C,DL)413. The child IAB node 403 may transmit a backhaul uplink signal to theIAB node 402 through a backhaul uplink L_(C,UL) 414. In theaforementioned example of FIGS. 4A and 4B, a subscript P means abackhaul link with the parent, a subscript A means an access link withthe UE, and a subscript C means a backhaul link with the child.

A link relationship of FIGS. 4A and 4B is described based on the IABnode 402. From the viewpoint of the child IAB node 403, the parent nodeis the IAB node 402, and the child IAB node 403 may have another IABchild node at a lower level. In addition, from the viewpoint of theparent node 401, the child node is the IAB node 402, and the parent node401 may have another IAB parent node at a higher level.

In the description above, a backhaul uplink/downlink signal and anaccess uplink/downlink signal may include data and control information,or a channel for transmitting the data and control information, or areference signal required to decode the data and control information, orat least one of reference signals for reporting channel information.

FIG. 4B illustrates an example in which multiplexing is performed in afrequency domain or a spatial domain.

Since the IAB node has the half-duplex constraints at a moment asdescribed above, signals which may be multiplexed in the frequencydomain or the spatial domain are constrained. For example, consideringthe half-duplex constrains of the IAB node 402, a link multiplexable ina time domain in which the IAB node is able to perform transmission maybe the backhaul uplink L_(P,UL) 412, the backhaul downlink L_(C,DL) 413,and the access downlink L_(A,DL) 416. Accordingly, when the links (e.g.,the backhaul uplink L_(P,UL) 412, the backhaul downlink L_(C,DL) 413,and the access downlink L_(A,DL) 416) are multiplexed in the frequencydomain or the spatial domain, the IAB node 402 may perform transmissionin the same time domain through all of the links as in a resource region421. In addition, the links multiplexable in the time domain in whichthe IAB node 402 is able to perform reception may be the backhauldownlink L_(P,DL) 411, the backhaul uplink L_(C,UL) 414, the accessuplink L_(A,UL) 415, or the like. Accordingly, when the links (i.e., thebackhaul downlink L_(P,DL) 411, the backhaul uplink L_(C,UL) 414, andthe access uplink L_(A,UL) 415) are multiplexed in the frequency domainor the spatial domain, the IAB node 402 may perform reception in thesame time domain through all of the links as in a resource region 422.

Multiplexing of the links provided in the embodiment of FIGS. 4A and 4Bis one example, and it is also possible to multiplex only two links outof three links multiplexed in the frequency or spatial domain. That is,the IAB node may transmit/receive a signal by multiplexing some ofmultiplexable links.

Next, a structure of the IAB node will be described.

Various types of base station structures which are optimal for a servicerequirement have been studied in a 5G system to support various servicessuch as high-capacity transmission, low-latency high-reliability, orlarge-scale IoT devices, and to reduce Capital Expenditures (CAPEX). Inorder to reduce the CAPEX and effectively process interference controlin a 4G LTE system, a Cloud RAN (C-RAN) structure has beencommercialized in which a data processor of the base station and a radiotransceiver (or a Remote Radio Head (RRH)) are separated so that thedata processor performs processing in a centralized manner and only theradio transceiver is disposed in a cell site. In the C-RAN structure,when the data processor of the base station transmits baseband digitalIn-phase Quadrature (IQ) data to the radio transceiver, an optical linkof a Common Public Radio Interface (CPRI) standard is used in general.When data is transmitted to the radio transceiver, a large data capacityis required. For example, 614.4 Mbps is required when transmittingInternet Protocol (IP) data of 10 MHz, and a transfer rate of 1.2 Gbpsis required when transmitting IP data of 20 MHz. Therefore, in order toreduce an enormous load of the optical link, a 5G RAN structure isdesigned to have various structures in such a manner that a base stationis separated into a Central Unit (CU) and a Distributed Unit (DU) and afunctional split is applied to the CU and the DU. Standardization isunderway for various functional split options between the CU and the DUin 3GPP. In the functional split options, splitting is achieved for eachfunction between protocol layers or within the protocol layer. The totalnumber of options is 8, i.e., from an option 1 to an option 8. Amongthem, a structure preferentially considered in the current 5G basestation structure is an option 2 and an option 7. In the option 2, anRRC and a Packet Data Convergence Protocol (PDCP) are located in the CU,and a Radio Link Control (RLC), a Medium Access Control (MAC), aPhysical Layer (PHY), and a Radio Frequency (RF) are located in the DU.In the option 7, an RRC, a PDCP, an RLC, a MAC, and a higher PHY layerare located in the CU, and a lower PHY layer is located in the DU.Through the aforementioned functional split, it is possible to have astructure with deployment flexibility to separate and move NR networkprotocols between the CU and the DU. Through this structure, flexible HWimplementation provides a cost-effective solution, and the separationstructure between the CU and the DU enables load management, real-timeperformance optimization adjustment, and Network FunctionsVirtualization (NFV)/Software Defined Network (SDN). The configurablefunctional split is advantageously applicable to various applicationexamples (a variable latency in transmission).

Therefore, the structure of the IAB node considering the aforementionedfunction split will be described with reference to FIG. 5.

FIG. 5 schematically illustrates a structure of an IAB node according toan embodiment of the disclosure.

Referring to FIG. 5, a gNB 501 is constructed of a CU and a DU, and IABnodes are constructed of a terminal function (hereinafter, MT) fortransmitting/receiving data on a parent node and a backhaul link and abase station function (hereinafter, DU) for transmitting/receiving datain a child node and a backhaul link. In FIG. 5, an IAB node #1 502 iswirelessly coupled to the gNB 501 with one hop, and an IAB node #2 503is wirelessly coupled to the gNB 501 via the IAB node #1 502 with twohops.

Referring to FIG. 5, the CU of the gNB 501 may control not only the DUof the gNB 501 but also DUs of all IAB nodes wirelessly coupled to thegNB 501, i.e., the IAB node #1 502 and the IAB node #2 503 (see 511 and512). The CU of the gNB 501 may allocate a radio resource to the DU sothat the DU is able to transmit/receive data with respect to an MT of alower IAB node thereof. The allocation of the radio resource may betransmitted to the DU through system information or a higher layersignal such as RRC information or a physical layer signal by using aninterface of an F1 Application Protocol (F1AP). The F1AP may refer tothe 3GPP TS 38.473 standard. In this case, the radio resource may beconstructed of a downlink time resource, an uplink time resource, aflexible time resource, or the like.

Hereinafter, a configuration of the radio resource for the TDM will bedescribed in detail based on the IAB node #2 503. In particular, theconfiguration of the radio resource according to embodiments of thedisclosure may be applied when resources are multiplexed in one carrierin a time domain between an access link and a backhaul link in an IABnode in FIGS. 3A and 3B. In addition, the configuration of the radioresource according to embodiments of the disclosure may also be appliedwhen a backhaul link and another backhaul link, or a backhaul link andan access link, are multiplexed in a frequency domain of differentcarriers in FIGS. 4A and 4B.

The downlink time resource is a resource which allows the DU of the IABnode #2 503 to transmit downlink control/data and signals to the MT ofthe lower IAB node. The uplink time resource is a resource which allowsthe DU of the IAB node #2 503 to receive uplink control/data signalsfrom the MT of the lower IAB node. The flexible time resource is aresource which may be utilized by the DU as the downlink time resourceor the uplink time resource, and how the flexible time resource will beused by the MT of the lower IAB node may be indicted by the downlinkcontrol signal of the DU. Upon receiving the downlink control signal,the MT of the lower IAB node determines whether the flexible timeresource will be utilized as the downlink time resource or the uplinktime resource. When the downlink control signal is not received, the MTof the lower IAB node does not perform a transmission/receptionoperation. That is, the MT does not monitor or decode the downlinkcontrol channel on the resource or does not measure a signal on theresource. The MT does not perform the transmission/reception operationon the aforementioned resource. That is, the MT does not monitor ordecode the downlink control channel on the resource or does not measurea signal on the resource. Regarding the downlink time resource, theuplink time resource, and the flexible time resource, two differenttypes (or three different types including the time resource unavailableall the time) may be indicated from the CU to the DU.

A first type is a soft type. The CU of the gNB 501 may configure asoft-type downlink time resource, uplink time resource, and flexibletime resource to the DU of the IAB node #2 503 by using an F1AP (aninterface between the CU and the DU). In this case, regarding theconfigured soft-type resources, the IAB node #1 502, which is a parentIAB (or a DU or the parent IAB) of the IAB node #2 503, may explicitly(e.g., by means of a DCI format) or implicitly indicate to the IAB node#2 503, which is a child IAB (or a DU of the child IAB), whether theresource is available or not available. That is, when it is indicatedthat a specific resource is available, the DU of the IAB node #2 503 mayutilize the resource for data transmission/reception with respect to theMT of the lower IAB node. That is, the DU of the IAB node #2 503 mayutilize the resource to perform transmission in case of a downlinksource and reception in case of an uplink resource. If it is indicatedthat the resource is unavailable, the IAB node #2 503 is not able toutilize the resource for data transmission/reception with respect to theMT of the IAB node. That is, the DU of the IAB node #2 503 is not ableto perform transmission/reception by utilizing the resource.

A method of indicating availability of the soft-type resource by using aDownlink Control Information (DCI) format will be described in greaterdetail. In this embodiment, DCI may include an availability indicatorfor indicating availability of one or more successive uplink or downlinkor flexible symbols.

In order to receive the DCI based on the DCI format, the IAB node #2 503may receive location information of the availability indicatorindicating the availability of the IAB node #2 in the DCI format, atable indicating availability for a time resource corresponding to aplurality of slots, and information on at least one mapping relationshipof the availability indicator by means of a higher layer signal from aCU or a parent IAB, together with a cell Identification (ID) of the DUof the IAB node #2 503. A value (or indicator) indicating theavailability of the successive uplink symbol, downlink symbol, orflexible symbol in one slot and the meaning of the value may beconfigured as shown in Table 1 below.

TABLE 1 Value Indication 0 No indication of availability for softsymbols 1 DL soft symbols are indicated available No indication ofavailability for UL and Flexible soft symbols 2 UL soft symbols areindicated available No indication of availability for DL and Flexiblesoft symbols 3 DL and UL soft symbols are indicated available Noindication of availability for Flexible soft symbols 4 Flexible softsymbols are indicated available No indication of availability for DL andUL soft symbols 5 DL and Flexible soft symbols are indicated availableNo indication of availability for UL soft symbols 6 UL and Flexible softsymbols are indicated available No indication of availability for DLsoft symbols 7 DL, UL, and Flexible soft symbols are indicated available

When the availability indicator is indicated from the parent IAB to theIAB node #2 503 through a DCI format and the IAB node #2 receives theindication, the DU of the IAB node #2 503 may consider a method ofinterpreting a relationship between the downlink, uplink, or flexibletime resource configured from the CU to the IAB DU and theaforementioned availability as follows.

A first method is a method in which the IAB DU expects that the numberof values indicating the availability included in the availabilityindicator included in the DCI format is equal to the number of slotsincluding a soft type constructed of successive symbols configured bythe CU. According to this method, the IAB DU may determine that theavailability is applied only to a slot including the soft type.

A second method is a method in which the IAB DU expects that the numberof values indicating the availability included in the availabilityindicator included in the DCI format is equal to the number of all slotsconfigured by the CU, i.e., all slots including ahard/soft/Non-Available (NA) type. Meanwhile, in this embodiment, theIAB DU may determine that the availability is applied only to a slotincluding the soft type, and may determine that the indicatedavailability is not applied to a slot including only the hard or the NAtype, without the soft type.

In the first and second methods, the IAB DU may expect that the meaningof the value indicating the availability matches a downlink resource,uplink resource, or flexible resource configured by the CU. For example,when only a downlink soft resource or a downlink hard resource ispresent in a slot, the IAB DU may expect that only a value of 1 isindicated in Table 1 above. Accordingly, it may be expected that valuesincluding the availability of the uplink soft resource are not indicatedamong the values in Table 1 above.

In addition, at least in a flexible resource configured by the CU, theIAB DU may determine that it is possible to indicate whether a downlinkresource is available or an uplink resource is available, in addition toa value indicating that the flexible resource is available. For example,in case of a flexible soft resource or a flexible hard resource, the DUof the IAB node may expect that it is possible to indicate a value of 1or 2, instead of a value of 4 in Table 1 above. In this case, the DU ofthe IAB node #2 may determine that the flexible resource is availableonly in an uplink or a downlink by an indication of the parent IAB,instead of being available in the uplink or downlink by thedetermination of the UIAB node #2.

In addition, the IAB DU expects that a value of 0 may be indicated inTable 1 above even in any hard/soft or NA resource configured by the CU.In this case, the IAB DU determines that the hard/soft resourceconfigured previously by the CU is not available, and until it isindicated that the resource is available at a later time according tothe DCI format, considers that the resource is not utilized for datatransmission/reception of the DU of the IAB node #2 with respect to theMT of the lower IAB node similarly to a case of an always unavailableresource type configured by the CU. Thereafter, when it is indicatedthat the resource is available again according to the DCI format, the DUof the IAB node #2 may utilize the resource as it is configured by theCU and received according to the DCI format.

The second type is a hard type, and the resources are always availablebetween the DU and the MT. That is, irrespective of atransmission/reception operation of the MT of the IAB node #2, the DU ofthe IAB node #2 may perform transmission when the resource is a downlinktime resource, and may perform reception when the resource is an uplinkresource. When the resource is a flexible resource, transmission orreception may be performed by the determination of the IAB DU (i.e., inaccordance with a DCI format indicating whether the flexible resource isa downlink resource or an uplink resource to the MT of the lower IABnode).

The third type is an always not-used or always non-available type, andthe resources are not utilized for data transmission/reception of the DUof the IAB node #2 with respect to the MT.

The above types are received together when a downlink time resource, anuplink time resource, a flexible time resource, and a reserved timeresource are received through a higher signal from the CU to the DU.

Referring to FIG. 5, the DU of the gNB 501 performs a typical basestation operation, and the DU controls the MT of the IAB node #1 501 toperform scheduling so that data is transmitted/received (see 521). TheDU of the IAB node #1 502 performs a typical base station operation, andthe DU controls the MT of the IAB node #2 503 to perform scheduling sothat data is transmitted/received (see 522).

According to an embodiment, the DU may indicate a radio resource so thatdata is transmitted/received with respect to the MT of the lower IABnode, based on a radio resource allocated from the CU. A configurationfor the radio resource may be transmitted to the MT through systeminformation or a higher layer signal or a physical layer signal. In thiscase, the radio resource may be constructed of a downlink time resource,an uplink time resource, a flexible time resource, a reserved timeresource, or the like. The downlink time resource is a resource whichallows the DU to transmit downlink control/data signals to the MT of thelower IAB node. The uplink time resource is a resource which allows theDU to receive uplink control/data signals from the MT of the lower IABnode. The flexible time resource is a resource which may be utilized bythe DU as the downlink time resource or the uplink time resource, andhow the flexible time resource will be used by the MT of the lower IABnode may be indicted by the downlink control signal of the DU. Uponreceiving the downlink control signal, the MT determines whether theflexible time resource will be utilized as the downlink time resource orthe uplink time resource. When the downlink control signal is notreceived, the MT does not perform a transmission/reception operation.That is, the MT does not monitor or decode the downlink control channelon the resource or does not measure a signal on the resource.

The downlink control signal may be signaled to the MT as a combinationof a higher layer signal and a physical layer signal, and the MT mayreceive the signaling to determine a slot format in a specific slot. Theslot format may be configured, by default, to start with a downlinksymbol and end with an uplink symbol, with a flexible symbol located inthe middle (e.g., a structure having order of D-F-U). When only the slotformat is used, the DU of the IAB node may perform downlink transmissionat the beginning of the slot. However, since the MT of the IAB node isconfigured with the aforementioned slot format (i.e., D-F-U structure),it is not possible to perform uplink transmission at the same time (seeslot format indices 0 to 55 in Table 2 below). Accordingly, the slotformat configured, by default, to start with the uplink symbol and endwith the downlink symbol, with the flexible symbol located in themiddle, may be exemplified as shown in Table 2 below (see slot formatindices 56 to 96 in Table 2 below). The slot format exemplified in Table2 below may be transmitted to the MT by using the downlink controlsignal, and may be configured in the DU from the CU by using the F1AP.

TABLE 2 For- Symbol number in a slot mat 0 1 2 3 4 5 6 7 8 9 10 11 12 130 D D D D D D D D D D D D D D 1 U U U U U U U U U U U U U U 2 F F F F FF F F F F F F F F 3 D D D D D D D D D D D D D F 4 D D D D D D D D D D DD F F 5 D D D D D D D D D D D F F F 6 D D D D D D D D D D F F F F 7 D DD D D D D D D F F F F F 8 F F F F F F F F F F F F F U 9 F F F F F F F FF F F F U U 10 F U U U U U U U U U U U U U 11 F F U U U U U U U U U U UU 12 F F F U U U U U U U U U U U 13 F F F F U U U U U U U U U U 14 F F FF F U U U U U U U U U 15 F F F F F F U U U U U U U U 16 D F F F F F F FF F F F F F 17 D D F F F F F F F F F F F F 18 D D D F F F F F F F F F FF 19 D F F F F F F F F F F F F U 20 D D F F F F F F F F F F F U 21 D D DF F F F F F F F F F U 22 D F F F F F F F F F F F U U 23 D D F F F F F FF F F F U U 24 D D D F F F F F F F F F U U 25 D F F F F F F F F F F U UU 26 D D F F F F F F F F F U U U 27 D D D F F F F F F F F U U U 28 D D DD D D D D D D D D F U 29 D D P D D D D D D D D F F U 30 D D D D D D D DD D F F F U

The reserved time resource (e.g., #97 to #254) is a resource in whichthe DU is not able to transmit/receive data with respect to the MT ofthe lower IAB node, and the MT does not perform a transmission/receptionoperation in the resource. That is, the MT may not monitor or decode adownlink control channel in the resource, or may not measure a signal inthe resource.

Accordingly, the MT in one IAB nodes is controlled by the DU in the IABnodes to receive scheduling so that data is transmitted/received, andthe DU in the same IAB nodes is controlled by the CU of the gNB 501.Therefore, since the MT and DU in one IAB are controlled by differententities, it is difficult to be coordinated on a real-time basis.

FIG. 6 is a drawing for explaining a communication method forsimultaneously performing transmission/reception between an MT and DU inan IAB node in a wireless communication system according to anembodiment of the disclosure.

In FIG. 6, simultaneous transmission/reception between the MT and DU inone IAB node means that the MT performs transmission or reception andthe DU performs transmission or reception in the same time resource atthe same time by using the multiplexing scheme (FDM or SDM) describedwith reference to FIGS. 2A and 2B or to be described with reference toFIGS. 7 and 8.

Referring to FIG. 6, a first case 601 shows that both the MT and the DUtransmit respective signals in one IAB node. In the first case 601, asignal transmitted by the MT of the IAB node may be received by theparent node or the DU of the base station through a backhaul uplink asdescribed with reference to FIGS. 3A, 3B, 4A, 4B, and/or 5. In addition,in the first case 601, a signal transmitted by the DU of the IAB node atthe same time (i.e., in the same time resource) may be received by theMT of the child IAB node through a backhaul downlink or may be receivedby an access terminal through an access downlink, as described withreference to FIGS. 3A, 3B, 4A, 4B, and/or 5.

A second case 602 shows that both the MT and the DU receive respectivesignals in one IAB node. In the second case 602, a signal received bythe MT of the IAB node may be a signal transmitted from the parent IABnode or the DU of the base station through a backhaul downlink asdescribed with reference to FIGS. 3A, 3B, 4A, 4B, and/or 5. In addition,in the second case 602, a signal received by the DU of the IAB node atthe same time (i.e., in the same time resource) may be a signaltransmitted by the MT of the child IAB node through a backhaul uplink ortransmitted by an access terminal through an access uplink, as describedwith reference to FIGS. 3A, 3B, 4A, 4B, and 5.

A third case 603 shows that both the MT and the DU receive or transmitrespective signals in the IAB node. That is, in the third case 603, theMT in the IAB node may receive a signal thereof, and the DU in the IABnode may transmit a signal thereof at the same time. In the third case603, a signal received by the MT of the IAB node may be a signaltransmitted from the parent IAB node or the DU of the base stationthrough a backhaul downlink as described with reference to FIGS. 3A, 3B,4A, 4B, and/or 5. In addition, in the third case 603, a signaltransmitted by the DU of the IAB node at the same time (i.e., in thesame time resource) may be received by the MT of the child IAB nodethrough a backhaul downlink or received by an access terminal through anaccess downlink, as described with reference to FIGS. 3A, 3B, 4A, 4B,and/or 5.

A fourth case 604 shows that both the MT and the DU transmit or receiverespective signals in the IAB node. That is, in the fourth case 604, theMT in the IAB node may transmit a signal thereof, and the DU in the IABnode may receive a signal thereof at the same time. In the fourth case604, a signal transmitted by the MT of the IAB node may be received bythe parent IAB node or the DU of the base station through a backhauluplink as described with reference to FIGS. 3A, 3B, 4A, 4B, and/or 5. Inaddition, in the fourth case 604, a signal received by the DU of the IABnode at the same time (i.e., in the same time resource) may be a signaltransmitted by the MT of the child IAB node through a backhaul uplink ortransmitted by an access terminal through an access uplink, as describedwith reference to FIGS. 3A, 3B, 4A, 4B, and/or 5.

The disclosure provides embodiments for a method of configuring a DUresource type in a situation where both the MT and the DU transmit orreceive respective signals in one IAB node in the first case 601 and/orthe second case 602, and a procedure of a parent IAB node and an IABnode according to the method. Hereinafter, embodiments of the disclosuremay be applied to not only the first case 601 and the second case 602but also the third case 603 and the fourth case 604.

FIG. 7 is a drawing for explaining a DU resource type for supporting FDMof an IAB node and an operation of an IAB node in a wirelesscommunication system according to an embodiment of the disclosure.

Referring to FIG. 7, when resources of the DU and MT of the IAB node aremultiplexed with FDM, the DU and MT of the IAB node performtransmission/reception simultaneously in adjacent frequency resources atthe same time, which results in occurrence of transmission/receptioninterference between the DU and MT of the IAB node. A guard frequencydomain may be considered to mitigate the transmission/receptioninterference. According to whether the guard frequency domain isgenerated by the DU of the IAB node or by the DU of the parent IAB node,a DU resource type of the IAB node in a frequency/time domain and anoperation of the DU and MT of the IAB node, based on the DU resourcetype, may vary. Accordingly, a method of configuring the DU resourcetype in the frequency-time domain, a method of generating a guardfrequency, and a DU and MT operation of the IAB node, based on the guardfrequency generation method and the DU resource type, will be descriedwith reference to FIG. 7.

Hereinafter, the disclosure discloses a DU resource type configurationin a frequency-time domain.

According to an embodiment, a DU of a gNB may allocate a radio resourceto a DU so that the DU is able to transmit/receive data with respect toan MT of a lower IAB node thereof. The allocation of the radio resourcemay be transmitted to the DU through system information or a higherlayer signal such as RRC information or a physical layer signal by usingan interface of an F1 Application Protocol (F1AP). In this case, theradio resource may be constructed of a downlink frequency-time resource,an uplink frequency-time resource, and/or a flexible frequency-timeresource, or the like. Unlike in a radio time resource which utilizes afull band in the carrier described in FIG. 5, a resource may beconfigured in a frequency-time domain corresponding to a specificfrequency (e.g., at least one Physical Resource Blocks (PRB) or afrequency domain in which the at least one PRB is allocated in units ofallocation on frequency) and a specific time (for example, at least oneslot) in one carrier. Hereinafter, frequency-time will be omitted forconvenience. Similarly to the description on the radio time resource,information on three types (or at least one of the three types) may beindicated from the CU to the DU of the IAB node with respect to thedownlink resource, uplink resource, and/or flexible resource. A firsttype is a soft type. The CU of the gNB may configure a soft-typedownlink resource, uplink resource, and flexible resource to the DU ofthe IAB node by using an F1AP (an interface between the CU and the DU).In this case, regarding the configured soft-type resources, the IABnode, which is a parent IAB (or a DU or the parent IAB) of the IAB node,may explicitly (e.g., by means of a DCI format) or implicitly indicateto the IAB node, which is a child IAB (or a DU of the child IAB),whether the resource is available or not available. That is, when it isindicated that a specific resource is available, the DU of the IAB nodemay utilize the resource for data transmission/reception with respect tothe MT of the lower IAB node. In addition, the DU of the IAB node mayutilize the resource to perform transmission in case of a downlinksource and reception in case of an uplink resource. If it is indicatedthat the resource is unavailable, the IAB node is not able to utilizethe resource for data transmission/reception with respect to the MT ofthe IAB node. That is, the DU of the IAB node is not able to performtransmission/reception by utilizing the resource.

Hereinafter, the disclosure discloses a method of indicatingavailability of a resource of the soft type by using a DCI format. Inthis embodiment, the DCI format may include an availability indicatorfor indicating availability of one or more successive uplink or downlinkor flexible symbols.

In order to receive the DCI format, the IAB node may receive locationinformation of the availability indicator indicating the availability ofthe IAB node in the DCI format, a table indicating availability for aplurality of frequency-time resources, and information on at least onemapping relationship of the availability indicator by means of a higherlayer signal from a CU or a parent IAB, together with a cellIdentification (ID) of the DU of the IAB node.

As an example, if a higher layer signal for availability indication ofthe soft time resource is reused for availability indication of a softtime-frequency resource to support FDM when the TDM is supported, theIAB node may determine that an availability indication value of anavailability indication table applied to an uplink/downlink/flexiblesymbol of a specific slot in a higher layer signal for availabilityindication of the soft time resource when the TDM is supported isapplied to a specific frequency Resource Block (RB) set of a softtime-frequency resource of the same slot. In this case, theaforementioned method may be applied when the number of specificfrequency RB sets of the soft time-frequency resource of the slot isone. Accordingly, when the availability indication value is applied to atime resource of a soft resource of a specific slot, whether it isapplied to a soft time-frequency resource of a specific RB set may beindicated by RRC signaling, MAC CE, or physical signaling (e.g., DCI)from a parent IAB regarding whether to use a TDM support resource (e.g.,the radio resource of FIG. 5) or whether to use an FDM support resource(e.g., the radio resource of FIG. 7). For example, when the IAB nodereceives an indication for using the TDM support resource, the IAB nodemay determine that the availability indication value is applied to thetime resource of the soft resource of the specific slot. In addition,when the IAB node receives an indication for using the FDM supportresource, the IAB node may determine that the availability indicationvalue is applied to the soft time-frequency resource of the specific RBset. Alternatively, whether the availability indication value is appliedto the time resource of the soft resource of the specific slot orapplied to the soft time-frequency resource of the specific RB set maybe determined by a determination of the IAB node for determining whetherto use the TDM support resource or whether to use the FDM supportresource. For example, when the IAB node determines that the TDM supportresource is used, the IAB node may determine that the availabilityindication value is applied to the time resource of the soft resource ofthe specific slot. In addition, when the IAB node determines that theFDM support resource is used, the IAB node may determine that theavailability indication value is applied to the soft time-frequencyresource of the specific RB set. The determination on the TDM or FDMsupport resource may be performed by the IAB node, based on whether tosatisfy one of conditions including power control for MT uplinktransmission of the IAB node in simultaneous transmission, power controlfor MT downlink reception of the IAB node in simultaneous reception,whether MT uplink transmission of the IAB node and DU downlinktransmission of the IAB node have matched timing in simultaneoustransmission, whether MT downlink reception of the IAB node and DUuplink reception of the IAB node have matched timing in simultaneousreception, or the like. The determination performed by the IAB node onwhether to use the TDM support resource or whether to use the FDMsupport resource may be reported to the parent IAB node or the CUthrough RRC signaling, MAC CE, or physical signaling (e.g., DCI).

According to an embodiment, the TDM support resource may be constructedof a downlink time resource, an uplink time resource, a flexible timeresource, a reserved time resource, or the like. According to anembodiment, the FDM support resource may be constructed of a downlinkfrequency-time resource, an uplink frequency-time resource, and/or aflexible frequency-time resource or the like.

As another example, the availability indication of the softtime-frequency resource for supporting the FDM is configured through anadditional higher layer signal other than a higher layer signal for theavailability indication of the soft time-frequency resource when the TDMis supported, a table indicating availability for the plurality offrequency-tome resources may include availability corresponding to atleast one frequency RB set starting from a slot (e.g., a slot i) inwhich the MT of the IAB node receives the DCI format. That is, a rowhaving a K-th index (mapped to an availability indicator K in the DCIformat) in the table may include an availability value corresponding toat least one frequency RB set in each of slots from a slot i to a sloti+N.

A mapping relationship of the availability indicator for the pluralityof frequency-time resources may be defined by using Table 3, Table 4, orTable 5 below. According to an embodiment, Table 3 may be defined in astandard so as to be utilized commonly when the TDM or the FDM issupported. In addition, according to an embodiment, Table 4 or Table 5may be defined in a standard to as to be utilized only when the FDM issupported.

TABLE 3 Value Indication 0 No indication of availability for softsymbols or RB set(s) 1 DL soft symbols or RB set(s) are indicatedavailable No indication of availability for UL and Flexible soft symbolsor RB set(s) 2 UL soft symbols or RB set(s)are indicated available Noindication of availability for DL and Flexible soft symbols or RB set(s)3 DL and UL soft symbols or RB set(s) are indicated available Noindication of availability for Flexible soft symbols or RB set(s) 4Flexible soft symbols or RB set(s) are indicated available No indicationof availability for DL and UL soft symbols or RB set(s) 5 DL andFlexible soft symbols or RB set(s) are indicated available No indicationof availability for UL soft symbols or RB set(s) 6 UL and Flexible softsymbols or RB set(s) are indicated available No indication ofavailability for DL soft symbols or RB set(s) 7 DL, UL, and Flexiblesoft symbols or RB set(s) are indicated available

TABLE 4 Value Indication 0 No indication of availability for soft RBset(s) 1 DL soft RB set(s) are indicated available No indication ofavailability for UL and Flexible soft RB set(s) 2 UL soft RB set(s)areindicated available No indication of availability for DL and Flexiblesoft RB set(s) 3 DL and UL soft RB set(s) are indicated available Noindication of availability for Flexible soft RB set(s) 4 Flexible softRB set(s) are indicated available No indication of availability for DLand UL soft RB set(s) 5 DL and Flexible soft RB set(s) are indicatedavailable No indication of availability for UL soft RB set(s) 6 UL andFlexible soft RB set(s) are indicated available No indication ofavailability for DL soft RB set(s) 7 DL, UL, and Flexible soft RB set(s)are indicated available

TABLE 5 Value Indication 0 No indication of availability for soft RBset(s) 1 Soft RB set(s) are indicated available

The second type is a hard type, and the resources are always utilizedbetween the DU and the MT. That is, irrespective of atransmission/reception operation of the MT of the IAB node, the DU ofthe IAB node may perform transmission when the resource is a downlinktime resource, and may perform reception when the resource is an uplinkresource. When the resource is a flexible resource, transmission orreception may be performed by the determination of the IAB DU (i.e., inaccordance with a DCI format indicating whether the flexible resource isa downlink resource or an uplink resource to the MT of the lower IABnode).

The third type is an always not-used or always Non-Available (NA) type,and the resources of this type are not available for datatransmission/reception of the DU of the IAB node with respect to the MT.

The above types are received together when a downlink resource, anuplink resource, a flexible resource, and a reserved resource arereceived through a higher signal from the CU to the DU.

Hereinafter, the disclosure discloses a method of generating a guardfrequency according to a DU resource type, and a DU and MT operation ofan IAB node.

As a first method, a method in which the guard frequency is generated bya DU of an IAB node which is a child IAB node of a base station/parentIAB node is disclosed. A first FIG. 700 of FIG. 7 illustrates that a DUresource type of the IAB node, i.e., a hard type 701, a soft type 702,and an NA type 703, is configured in a frequency-time domain by a CU. Inthis case, it is assumed that the DU of the IAB node determines that aresource of the soft type 702 is not utilized. A resource 711 utilizedin data transmission/reception in practice by the DU of the IAB node anda resource 713 utilized in data transmission/reception in practice bythe MT of the IAB node with respect to the base station/parent IAB nodemay be present in a resource of the aforementioned type. In this case, aguard frequency domain 712 may be configured in a resource of the hardtype 701 to mitigate an effect of DU transmission/reception of the IABnode on MT transmission/reception of the IAB node. A time-frequencyresource in the hard type 701 is a resource which may be utilized by theDU of the IAB node irrespective of the effect of the MT of the IAB node.In the remaining time-frequency domain other than the hard type 701,that is, a soft type 702 determined as not to be utilized by the IAB DUand an NA type 703 not available for the IAB DU, the guard frequencydomain may be configured within a resource of the hard type 701 underthe responsibility of the DU of the IAB node so that datatransmission/reception of the base station/parent IAB node and the MT ofthe IAB node is not affected by interference.

A second FIG. 720 of FIG. 7 illustrates another example in which a DUresource type of the IAB node, i.e., a hard type 721, a soft type 722,and an NA type 723, is configured in a frequency-time domain by a CU. Inthis case, it is assumed that the DU of the IAB node determines that aresource of the soft type 722 is utilized. A resource 731 utilized indata transmission/reception in practice by the DU of the IAB node and aresource 733 utilized in data transmission/reception in practice by theMT of the IAB node with respect to the base station/parent IAB node maybe present in a resource of the aforementioned type. In this case, aguard frequency domain 732 may be configured in a resource of the softtype 722 determined to be utilized by the DU of the IAB node, so as tomitigate an effect of DU transmission/reception of the IAB node on MTtransmission/reception of the IAB node. A time-frequency resource in thesoft type 722 is a resource which may be utilized by the DU of the IABnode without having an effect on the MT of the IAB node. In theremaining time-frequency domain other than the hard type 721 and thesoft type 722, that is, an NA type 723 not available for the IAB DU, theguard frequency domain may be configured within a resource of the softtype 722 determined to be utilized by the DU of the IAB under theresponsibility of the DU of the IAB node so that datatransmission/reception of the base station/parent IAB node and the MT ofthe IAB node is not affected by interference.

In summary, as the first method, in a method in which the guardfrequency is generated by the DU of the IAB node which is the child IABnode of the base station/parent IAB node, the DU of the IAB node maytransmit/receive data, without considering an effect on the MT of theIAB node operating at the same time-frequency in the resource of thehard type. However, a guard frequency may be configured within thehard-type resource to mitigate an effect of interference on the MT ofthe IAB node operating in another time-frequency.

Next, the DU of the IAB node may transmit/receive data, without havingan effect on the MT of the IAB node operating at the same time-frequencyin the soft-type resource determined to be utilized. Not having aneffect on the MT of the IAB node may be described as following cases.That is, the MT of the IAB node does not perform transmission/receptionduring a frequency-time resource of the DU of the IAB node.Alternatively, transmission/reception of the DU of the IAB node duringthe frequency-time resource does not lead to a change intransmission/reception of the MT of the IAB node. Alternatively, the MTof the IAB node receives a DCI format indicating that the soft-typeresource is available. However, to mitigate an effect of interference onthe MT of the IAB node operating in the remaining time-frequency otherthan the hard-type resource, a guard frequency may be configured in thesoft-type resource determined to be available.

As a second method, a method in which the guard frequency is generatedby a base station/parent IAB node which performs transmission/receptionwith respect to an MT of an IAB node which is a child node is described.A third FIG. 750 of FIG. 7 illustrates that a DU resource type of theIAB node, i.e., a hard type 751, a soft type 752, and an NA type 753, isconfigured in a frequency-time domain by a CU. In this case, it isassumed that the DU of the IAB node determines that a resource of thesoft type 752 is not utilized. A resource 761 utilized in datatransmission/reception in practice by the DU of the IAB node and aresource 763 utilized in data transmission/reception in practice by theMT of the IAB node with respect to the base station/parent IAB node maybe present in a resource of the aforementioned type. In this case, aguard frequency domain 762 may be configured in a resource of the softtype 752 to mitigate an effect of DU transmission/reception of the IABnode on MT transmission/reception of the IAB node. A time-frequencyresource in the hard type 751 is a resource which may be utilized by theDU of the IAB node without having to consider the effect on the MT ofthe IAB node Due to transmission/reception in the hard type 751, in theremaining time-frequency domain other than the hard type 751, that is, asoft type 752 determined as not to be utilized by the IAB DU and an NAtype 753 not available for the IAB DU, an effect of interference on datatransmission/reception of the base station/parent IAB node and the MT ofthe IAB node is not considered. Therefore, the guard frequency domain762 may be configured within the resource of the soft type 752 under theresponsibility of the DU of the base station/parent IAB node so thatthere is no effect of interference.

A fourth FIG. 770 of FIG. 7 illustrates another example in which a DUresource type of the IAB node, i.e., a hard type 771, a soft type 772,and an NA type 773, is configured in a frequency-time domain by a CU. Inthis case, it is assumed that the DU of the IAB node determines that aresource of the soft type 772 is utilized. A resource 781 utilized indata transmission/reception in practice by the DU of the IAB node and aresource 783 utilized in data transmission/reception in practice by theMT of the IAB node with respect to the base station/parent IAB node maybe present in a resource of the aforementioned type. In this case, aguard frequency domain 782 may be configured in a resource of the NAtype 773 determined not to be available for the DU of the IAB node, soas to mitigate an effect of DU transmission/reception of the IAB node onMT transmission/reception of the IAB node. A time-frequency resource inthe soft type 772 is a resource which may be utilized by the DU of theIAB node without having an effect on the MT of the IAB node. Due totransmission/reception in the soft type 722, in the remainingtime-frequency domain other than the hard type 771, that is, an NA type773 not available for the IAB DU, the DU of the IAB node does notconsider an effect of interference on data transmission/reception of thebase station/parent IAB node and the MT of the IAB node. Therefore, theguard frequency domain 782 may be configured within the resource of theNA type 773 under the responsibility of the DU of the basestation/parent IAB node so that there is no effect of interference.

In summary, as the second method, in a method in which the guardfrequency is generated by the DU of the base station/parent IAB nodewhich performs transmission/reception with respect to the MT of the IABnode, the DU of the IAB node may transmit/receive data, withoutconsidering an effect on the MT of the IAB node operating at the sametime-frequency in the resource of the hard type. However, an effect ofinterference on the MT of the IAB node operating in a differenttime-frequency is not considered, and the base station/parent IAB nodemay configure the guard frequency within the soft-type resourcedetermined as not to be available to mitigate the interference.

Hereinafter, the disclosure may transmit/receive data without affectingthe MT of the IAB node operating within the same time-frequency in thesoft-type resource determined to be available. However, the DU of theIAB node does not consider the interference effect on the MT of the IABnode operating in a different time-frequency other than the soft-typeand hard-type resources. In order to mitigate the interference, the basestation/parent IAB node may configure the guard frequency in the NA-typeresource configured to be available.

The method of configuring the guard frequency may be limited to a casewhere the guard frequency is necessary, and the configuring of the guardfrequency may be coordinated between the IAB node and the basestation/parent IAB node. That is, when it is necessary to configure theguard frequency (or when the IAB node reports that it has capability ofutilizing FDM), the IAB node may report the necessity of the guardfrequency to the base station/parent IAB node through a higher layersignal (e.g., RRC signaling, MAC CE)/physical signal (e.g.,DCI)/backhaul signal, and the base station/parent IAB node may indicatethe configuration of the guard frequency through the higher layersignal, physical signal/backhaul signal.

Which method will be used may be determined in a standard, and whetherto use the first method or the second method may be indicated to the IABnode, which is the child IAB node, by the DU of the base station/parentIAB node through the higher layer signal/physical signal or the backhaulsignal. The IAB node may receive the indication and apply the method ofconfiguring the guard frequency. Alternatively, the first method and thesecond method may be both used so that the guard frequency is configuredby each of the IAB node and the base station/parent IAB node, therebycancelling the interference effect to the maximum extent possible.

The guard frequency configured by using the first method or the secondmethod may be shared by being transmitted/received through the higherlayer signal/physical signal/backhaul signal between the IAB node andthe base station/parent IAB node.

In the first method or the second method, an allocation position in afrequency domain of a DU resource type may be as follows. A hard type, asoft type, and an NA type may be configured sequentially by a CU in anascending order or descending order of a frequency (PRB) index, and theIAB node may receive the configuration. In case of the soft type, the CUmay be configured or the base station/parent IAB node may be indicatedby the DCI format so that a soft type determined to be utilized by theIAB DU may be located after the hard type, and a soft type determined tobe utilized by the IAB DU may be located before the NA type, and the IABnode may receive the configuration and the indication.

FIG. 8 illustrates a DU resource type for supporting SDM of an IAB nodeand an operation of the IAB node in a wireless communication systemaccording to an embodiment of the disclosure.

Referring to FIG. 8, when the resource of the MT and DU of the IAB nodeis multiplexed with SDM, an upper part of FIG. 8 schematicallyillustrates that a base station/parent IAB node 801 and IAB nodes 802and 803 which are child IAB nodes transmit/receive data by utilizingSDM, that is, by using beams 811, 812, and 813 in a spatial domain. Thebase station/parent IAB node 801 may configure up to 128 TransmissionConfiguration Indication (TCI) states to the IAB nodes 802 and 803 forthe MT and DU of the IAB node through a higher layer signal/backhaulsignal. The TCI state may include beam-related information as follows.

-   -   TCI state ID    -   At least one Quasi-Co-Location (QCL) information    -   The QCL information may include a cell ID, a Bandwidth Part        (BWP, a reference signal (e.g., CSI-RS ID information when the        reference signal is CSI-RS, SSB index information when the        reference signal is SSB), and information on whether the QCL        type is a type A, a type B, a type C, or a type D.

Next, the base station/parent IAB node 801 may activate up to 8 TCIstates for the MT and DU of the IAB node among up to 128 TCI states tothe IAB nodes 802 and 802 through a MAC CE signal/backhaul signal.

The base station/parent IAB node 801 may indicate at least one TCI stateto the IAB nodes 802 and 803 among the up to 8 activated TCI statesthrough a physical signal. The MT and DU of the IAB node maytransmit/receive data through at least one specific beam based on theindicated at least one TCI state.

In this case, the DU 803 of the IAB node may coordinate a beam to beused with the base station/parent IAB node 801.

As a first method for coordinating a beam, a CU may configure a hardtype 851, a soft type 852, and an NA type 853 to the DU 803 for specificbeams corresponding to the TCI state. In other words, a DU resource typemay be configured in units of the beam. In a beam of the hard type 851,the DU 803 of the IAB node may transmit/receive data by utilizing thebeam of the hard type 851 irrespective of an effect on atransmission/reception beam of the MT 802 of the IAB node. In a beam ofthe soft type 852, the DU 803 of the IAB node may transmit/receive databy utilizing the beam of the soft type 852 without having an effect onthe transmission/reception beam of the MT 802 of the IAB node. Nothaving an effect on the MT 802 of the IAB node may be further describedas following cases. That is, the MT of the IAB node does not performtransmission/reception during a frequency-time resource of the DU of theIAB node. Alternatively, transmission/reception of the DU of the IABnode during the frequency-time resource does not lead to a change intransmission/reception of the MT of the IAB node. Alternatively, the MTof the IAB node receives a DCI format indicating that the soft-typeresource is available.

Next, in a beam of the NA type 853, the DU 803 of the IAB node does nottransmit/receive data.

As a second method for coordinating beams 861 and 862, a CU mayalternately configure the hard type 851, the soft type 852, and the NAtype 853 to the DU 803 during a specific time (a slot or a symbol) forspecific beams corresponding to the TCI state. The base station/parentIAB node 801 may transmit the configuration information to the IAB nodethrough a higher layer signal (e.g., RRC signaling, MAC CE)/backhaulsignal. The configuration information may include bitmap information fora hard type, soft type, and NA type at a specific time, period andoffset information of each hard type, soft type, and NA type, and TCIstate information to which the DU type information is applied.

As a third method for coordinating a beam, a CU may configure only thehard type and the NA type to the DU 803 for specific beams correspondingto the TCI state. In case of the soft type, it is difficult to determinean effect of the DU of the IAB node on the MT of the IAB node in thesoft type. Therefore, it is possible to apply only the hard type and theNA type. The hard type and the NA type may be applied by using the firstor second method.

As a fourth method for coordinating a beam, a CU may configure only abeam available or non-available for the DU, instead of the hard type andthe NA type, to the DU 803 of the IAB node for specific beamscorresponding to the TCI state. The beam available for the DU or thebeam non-available for the DU may be configured by the basestation/parent IAB node through a higher layer signal/backhaul signal.In some embodiments, the available beam and the non-available beam maybe fixed regardless of time, and information on such a beam may beconfigured. In addition, in some embodiments, the configurationinformation may include information (e.g., bitmap information) on a beamavailable or non-available for the DU at a specific time. In addition,in some embodiments, the configuration information may include periodand offset information for the beam available or non-available for theDU. In addition, in some embodiments, the configuration information mayinclude TCI state information to which information of the available beamand/or the non-available beam at the time is applied. The configurationinformation according to embodiments of the disclosure may be configuredto include at least one or combinations of the aforementionedinformation.

FIG. 9A illustrates an operation of a base station/parent IAB node in awireless communication system according to an embodiment of thedisclosure.

Referring to FIG. 9A, in operation 901, the base station/parent IAB node(e.g., the parent IAB illustrated in FIGS. 7 and/or 8) may transmit FDMor SDM-related information to the IAB node and receive necessaryinformation from the IAB node. As described above, the information mayinclude information required for switching to the FDM or the SDM,information required to support the FDM or the SDM, or the like. Theinformation required to support the FDM or the SDM may include radioresource allocation information including a DU resource type,information related to resource availability of a soft type, informationon necessity of a guard frequency, information on a method ofconfiguring the guard frequency, TCI state configuration information, DUresource type configuration information for specific beams correspondingto a TCI state, and/or configuration information on whether the DU isavailable or not-available. In operation 902, the base station/parentIAB node may transmit/receive backhaul data with respect to the IAB nodeby applying the FDM or the SDM.

FIG. 9B illustrates an operation of an IAB node which is a child IABnode in a wireless communication system according to an embodiment ofthe disclosure.

Referring to FIG. 9B, in operation 911, the IAB node may receive FDM orSDM-related information from a base station/parent IAB node and transmitnecessary information to the base station/parent IAB node. As describedabove, the information may include information required for switching tothe FDM or the SDM, information required to support the FDM or the SDM,or the like. The information required to support the FDM or the SDM mayinclude radio resource allocation information including a DU resourcetype, information related to resource availability of a soft type,information on necessity of a guard frequency, information on a methodof configuring the guard frequency, TCI state configuration information,DU resource type configuration information for specific beamscorresponding to a TCI state, and/or configuration information onwhether the DU is available or not-available. In operation 912, the IABnode may transmit/receive backhaul data with respect to the basestation/parent IAB node by applying the FDM or the SDM.

In order to perform the embodiments of the disclosure, FIGS. 10 and 11illustrate a transmitter, receiver, and processor of a terminal and basestation, respectively. The transmitter and the receiver may be referredto as a transceiver. In addition, FIG. 12 illustrates a device of theIAB node. The aforementioned embodiments illustrate atransmission/reception method of a base station (a donor base station)which performs transmission/reception in a backhaul link with respect tothe IAB node through mmWave and a terminal which performstransmission/reception in an access link with respect to the IAB node,when a signal is transmitted/received in the backhaul link or the accesslink through an IAB node in a 5G communication system. To perform this,the transmitter, receiver, and processor of the base station, terminal,and IAB node may operate according to each of the embodiments.

FIG. 10 illustrates a structure of a terminal according to an embodimentof the disclosure.

Referring to FIG. 10, the terminal of the disclosure may include aprocessor 1001, a receiver 1002, and a transmitter 1003.

The processor 1001 may control a series of processes so that theterminal operates, based individually or in combination on embodimentsof the disclosure described above with reference to FIGS. 1, 2A, 2B, 3A,3B, 4A, 4B, and 5 to 8. For example, access link transmission/receptionor the like with respect to an IAB node according to embodiments of thedisclosure may be controlled differently. The receiver 1002 and thetransmitter 1003 may be collectively referred to as a transceiver in anembodiment of the disclosure. The transceiver may transmit/receive asignal with respect to a base station. The transceiver maytransmit/receive a signal with respect to the base station. The signalmay include at least one of control information and data. To this end,the transceiver may include an RF transmitter which up-converts andamplifies a frequency of a signal to be transmitted and an RF receiverwhich performs low-noise amplification on a signal to be received anddown-converts a frequency of the signal. In addition, the transceivermay receive a signal through a wireless channel and output the signal tothe processor 1001, and may transmit the signal output from theprocessor 1001 through the wireless channel.

FIG. 11 illustrates a structure of a base station (a donor base station)according to an embodiment of the disclosure.

Referring to FIG. 11, the base station of the disclosure may include aprocessor 1101, a receiver 1102, and/or a transmitter 1103.

The processor 1101 may control a series of processes so that the basestation operates, based individually or in combination on embodiments ofthe disclosure described above with reference to FIGS. 1, 2A, 2B, 3A,3B, 4A, 4B, and 5 to 8. For example, backhaul linktransmission/reception and access link transmission/reception or thelike with respect to an IAB node according to embodiments of thedisclosure may be controlled differently. The receiver 1102 and thetransmitter 1103 may be collectively referred to as a transceiver in anembodiment of the disclosure. The transceiver may transmit/receive asignal with respect to a terminal or a lower (child) IAB node. Thesignal may include at least one of control information and data. To thisend, the transceiver may include an RF transmitter which up-converts andamplifies a frequency of a signal to be transmitted and an RF receiverwhich performs low-noise amplification on a signal to be received anddown-converts a frequency of the signal. In addition, the transceivermay receive a signal through a wireless channel and output the signal tothe processor 1101, and may transmit the signal output from theprocessor 1101 through the wireless channel.

FIG. 12 illustrates a structure of an IAB node according to anembodiment of the disclosure.

Referring to FIG. 12, according to an embodiment of the disclosure, theIAB node is an IAB node which performs transmission/reception withrespect to a lower (child) IAB node through a (wireless) backhaul link,and may include a base station function controller 1201, a base stationfunction receiver 1202, and a base station function transmitter 1203,and the IAB node. In addition, the IAB node is an IAB node whichinitially accesses to a higher (parent) IAB node and/or a donor basestation and transmits/receives a higher layer signal beforetransmission/reception is performed through a backhaul link and performstransmission/reception with respect to the higher (parent) IAB node andthe donor base station through a (wireless) backhaul link, and mayinclude a terminal function controller 1211, a terminal functionreceiver 1212, and a terminal function transmitter 1213.

The base station function controller 1201 of the IAB node may control aseries of processes so that the IAB node operates together with the basestation according to the aforementioned embodiment of the disclosure,and for example, may perform the aforementioned function of the DU ofthe IAB node. For example, the base station function controller 1201 maydifferently control backhaul link transmission/reception with respect toa lower IAB node and access link transmission/reception with respect tothe terminal according to an embodiment of the disclosure. The basestation function receiver 1202 and the base station function transmitter1203 may be collectively referred to as a first transceiver in anembodiment of the disclosure. The first transceiver may transmit/receivea signal with respect to a lower (child) IAB node and the terminal. Thesignal may include at least one of control information and data. To thisend, the first transceiver may include an RF transmitter whichup-converts and amplifies a frequency of a signal to be transmitted andan RF receiver which performs low-noise amplification on a signal to bereceived and down-converts a frequency of the signal. In addition, thefirst transceiver may receive a signal through a wireless channel andoutput the signal to the base station function controller 1201, and maytransmit the signal output from the base station function controller1201 through the wireless channel.

The terminal function controller 1211 of the IAB node may control aseries of processes in which a lower (child) IAB node operates togetherwith a terminal to transmit/receive data with respect to a donor basestation or a higher (parent) IAB node according to the aforementionedembodiment of the disclosure, and for example, may perform theaforementioned function of the MT of the IAB node. For example, theterminal function controller 1211 may differently controltransmission/reception through a (wireless) backhaul link with respectto the donor base station and/or the higher (parent) node according toan embodiment of the disclosure. The terminal function receiver 1212 andthe terminal function transmitter 1213 may be collectively referred toas a second transceiver in an embodiment of the disclosure. The secondtransceiver may transmit/receive a signal with respect to the donor basestation and the higher IAB node. The signal may include at least one ofcontrol information and data. To this end, the second transceiver mayinclude an RF transmitter which up-converts and amplifies a frequency ofa signal to be transmitted and an RF receiver which performs low-noiseamplification on a signal to be received and down-converts a frequencyof the signal. In addition, the second transceiver may receive a signalthrough a wireless channel and output the signal to the terminalfunction controller 1211, and may transmit the signal output from theterminal function controller 1211 through the wireless channel.

Meanwhile, the base station function controller 1210 of the IAB nodeincluded in the IAB node of FIG. 12 and the terminal function controller1211 of the IAB node may be integrated with each other and implementedas an IAB node controller. In this case, the IAB node controller 1200may control functions of the DU and MT together in the IAB node. Thebase station function controller 1201, the terminal function controller1211, and the IAB node controller may be implemented as at least oneprocessor. The first transceiver and the second transceiver may beprovided individually or may be implemented as one integratedtransmitter.

A beam described in the specification means a spatial flow of a signalin a wireless channel, and is formed by one or more antennas (or antennaelements). Such a forming process may be referred to as beamforming.According to various embodiments, an antenna array or the like in whicha plurality of antenna elements are deployed densely may be used. Inthis case, a shape (e.g., coverage) depending on a signal gain may havedirectivity. A beam used in signal transmission may be referred to as atransmission beam, and a beam used in signal reception may be referredto as reception beam. That is, as an example of one implementation, theIAB node may include an antenna array for the MT or an antenna array forthe DU.

When the IAB node transmits a signal in the direction of thetransmission beam, a signal gain of the device may increase. When thesignal is transmitted by using the transmission beam, the signal may betransmitted through a spatial domain reception filter of a signaltransmitting side, i.e., a transmitting end. When a signal istransmitted using a plurality of transmission beams, the transmittingend may transmit the signal while changing a spatial domain transmissionfilter. For example, when the signal is transmitted using the sametransmission beam, the transmitting end may transmit the signal throughthe same spatial domain transmission filter. For example, when the MT ofthe IAB node receives CSI-RSs for reception beam search (e.g., 3GPP TS38.214 repetition=‘on’), the IAB node may assume that the CSI-RSs aretransmitted through the same spatial domain transmission filter.

When the IAB node receives a signal in the direction of the receptionbeam, a signal gain of the device may increase. When the signal isreceived by using the reception beam, the signal may be received througha spatial domain reception filter of a signal receiving side, i.e., areceiving end. For example, when the IAB node simultaneously receivesseveral signals transmitted using different beams, the IAB node mayreceive the signals by using a single spatial domain receive filter, ormay receive the signals by using multiple simultaneous spatial domainreceive filters.

In addition, in the specification, a reference signal may be used as asignal transmitted using a beam, and may include, for example, aDemodulation-Reference Signal (DM-RS), a Channel StateInformation-Reference Signal (CSI-RS), a Synchronization Signal/PhysicalBroadcast Channel (SS/PBCH), and a Sounding Reference Signal (SRS). Inaddition, as a configuration for each reference signal, an indicatorsuch as a CSI-RS resource or an SRS-resource or the like may be used,and this configuration may include information associated with the beam.The information associated with the beam may mean whether acorresponding configuration (e.g., CSI-RS resource) uses the samespatial domain filter of another configuration (e.g., another CSI-RSresource in the same CSI-RS resource set) or uses another spatial domainfilter, or to which reference signal it is subjected to Quasi-Co-Located(QCL), and if it is subjected to the QCL, which type (e.g., QCL type A,B, C, D) it is. The QCL type may be defined as follows.

-   -   ‘QCL-TypeA’: {Doppler shift, Doppler spread, average delay,        delay spread}    -   ‘QCL-TypeB’: {Doppler shift, Doppler spread}    -   ‘QCL-TypeC’: {Doppler shift, average delay}    -   ‘QCL-TypeD’: {Spatial Rx parameter}

In the specification, according to various embodiments, the IAB node maymeasure beam quality to obtain cell quality and per-duplex quality. TheIAB node may obtain beam quality, based on a CSI-RS or SS/PBCH block.

On the other hand, embodiments of the disclosure disclosed in thespecification and drawings are presented only as a specific example forclarity and are not intended to limit the scope of the disclosure. Thatis, it is apparent to those of ordinary skill in the art to which thedisclosure pertains that other modifications based on the technicalconcept of the disclosure are possible. In addition, each of theembodiments may be operated optionally in combination with each other.

The methods according to the embodiments described in the claims or thedetailed description of the disclosure may be implemented in hardware,software, or a combination of hardware and software.

When the methods are implemented in software, a computer-readablerecording medium having one or more programs (software modules) recordedthereon may be provided. The one or more programs recorded on thecomputer-readable recording medium are configured to be executable byone or more processors in a device. The one or more programs includeinstructions to execute the methods according to the embodimentsdescribed in the claims or the detailed description.

The programs (e.g., software modules or software) may be stored inrandom access memory (RAM), non-volatile memory including flash memory,read-only memory (ROM), electrically erasable programmable read-onlymemory (EEPROM), a magnetic disc storage device, a compact disc-ROM(CD-ROM), a digital versatile disc (DVD), another type of opticalstorage device, or a magnetic cassette. Alternatively, the programs maybe stored in a memory system including a combination of some or all ofthe above-mentioned memory devices. In addition, each memory device maybe included by a plural number.

The programs may also be stored in an attachable storage device which isaccessible through a communication network such as the Internet, anintranet, a local area network (LAN), a wireless LAN (WLAN), or astorage area network (SAN), or a combination thereof. The storage devicemay be connected through an external port to an apparatus according theembodiments of the disclosure. Another storage device on thecommunication network may also be connected to the apparatus performingthe embodiments of the disclosure.

In the afore-described embodiments of the disclosure, elements includedin the disclosure are expressed in a singular or plural form accordingto the embodiments. However, the singular or plural form isappropriately selected for convenience of explanation and the disclosureis not limited thereto. As such, an element expressed in a plural formmay also be configured as a single element, and an element expressed ina singular form may also be configured as plural elements.

While the disclosure has been shown and described with reference tovarious embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the disclosure as definedby the appended claims and their equivalents.

What is claimed is:
 1. A method performed by a first integrated accessand backhaul (IAB) node in wireless communication, the methodcomprising: receiving resource allocation information includinginformation on a type of wireless resource controlled by a distributedunit (DU) of the first IAB node; and identifying a guard frequencyregion for mitigating interference between a data transmission orreception of a mobile termination (MT), and a data transmission orreception of the DU.
 2. The method of claim 1, wherein the informationon the type of wireless resource controlled by the DU includes a softtype indicating whether a radio resource is available by the DU, a hardtype in which the radio resource is always used, and a non-available(NA) type in which the radio resource is not always available.
 3. Themethod of claim 2, wherein the hard type, the soft type, and the NA typeare sequentially allocated by a central unit (CU) according to adescending order of a physical resource block (PRB) index.
 4. The methodof claim 2, wherein the hard type, the soft type, and the NA type aresequentially allocated by a central unit (CU) according to an ascendingorder of a physical resource block (PRB) index.
 5. The method of claim1, transmitting, to a second IAB node, information on a need for a guardfrequency region via a higher layer signaling.
 6. The method of claim 2,wherein the identifying of the guard frequency region comprises: in casethat a resource of the soft type is available, one of a region of theresource of soft type and a region of the resource of the hard type isidentified as the guard frequency region; and in case that a resource ofthe soft type is not available, a region of the resource of the hardtype is identified as the guard frequency region.
 7. The method of claim2, wherein the method further comprises receiving, from a second IABnode, configuration information on the guard frequency region, andwherein the identifying the guard frequency region comprise identifyingthe guard frequency region based one the configuration information onthe guard frequency region.
 8. The method of claim 7, wherein theconfiguration information on the guard frequency region includesinformation indicating to set the guard frequency region as the NA typeof frequency region, and information indicating to set the guardfrequency region as the soft type of frequency region in case that thesoft type of the frequency region is not available.
 9. A firstintegrated access and backhaul (IAB) node in wireless communication, thefirst IAB comprising: at least one transceiver; and at least oneprocessor operably connected to the at least one transceiver, whereinthe at least one processor is configured to: receive resource allocationinformation including information on a type of wireless resourcecontrolled by a distributed unit (DU) of the first IAB node, andidentify a guard frequency region for mitigating interference between adata transmission or reception of a mobile termination (MT), and a datatransmission or reception of the DU.
 10. The first IAB node of claim 9,wherein the information on the type of wireless resource controlled bythe DU includes a soft type indicating whether a radio resource isavailable by the DU, a hard type in which the radio resource is alwaysused, and a non-available (NA) type in which the radio resource is notalways available.
 11. The first IAB node of claim 10, wherein the hardtype, the soft type, and the NA type are sequentially allocated by acentral unit (CU) according to a descending order of a physical resourceblock (PRB) index.
 12. The first IAB node of claim 10, wherein the hardtype, the soft type, and the NA type are sequentially allocated by acentral unit (CU) according to an ascending order of a physical resourceblock (PRB) index.
 13. The first IAB node of claim 9, wherein the atleast one processor is further configured to: transmit, to a second IABnode, information on a need for the guard frequency region via a higherlayer signaling.
 14. The first IAB node of claim 10, wherein the atleast one processor is, to identify of the guard frequency region, isfurther configured to: in case that a resource of the soft type isavailable, one of a region of the resource of soft type and a region ofthe resource of the hard type is identified as the guard frequencyregion; and in case that a resource of the soft type is not available, aregion of the resource of the hard type is identified as the guardfrequency region.
 15. The first IAB node of claim 10, wherein the atleast one processor is further configured to receive, from a second IABnode, configuration information on the guard frequency region, andwherein the at least one processor is, to identify the guard frequencyregion, is further configured to identify the guard frequency regionbased one the configuration information on the guard frequency region.16. The first IAB node of claim 15, wherein the configurationinformation on the guard frequency region includes informationindicating to set the guard frequency region as the NA type of frequencyregion, and information indicating to set the guard frequency region asthe soft type of frequency region in case that the soft type of thefrequency region is not available.